Conventionally, a circuit that meets a required specification is designed using a circuit simulator by digitizing connection information about the circuit and checking whether or not the resulting data meets the required specification.
A circuit element forming the actual circuit varies in characteristics with time during operation, unlike an ideal model of the circuit element obtained by simulation. Such a circuit element having variable characteristics can disable, or cause malfunction of, a system that incorporates the circuit element.
To prevent the disabling or malfunction of the system, it is effective to perform a simulation that takes into consideration the degradation of the circuit element with time when designing the circuit. In actual, some commercially available circuit simulators incorporate a tool that modifies a circuit element model to allow for the aging degradation of the characteristics of the circuit element.
However, conventional circuit simulators have a problem that they cannot always design a circuit that reflects the aging degradation of the electrical characteristics of the actual circuit element.